A solid polymer fuel cell (hereinafter, may be referred to as “fuel cell”) simultaneously generates electric power and heat by electrochemically reacting a fuel gas including hydrogen with an oxidant gas including oxygen.
FIG. 1 illustrates a cross-sectional view of a cell 10, which is a constituent unit of a general fuel cell. A general fuel cell is configured such that several dozen to several hundred units of the cell 10 are laminated, the laminate is sandwiched between end plates, with a current collector plate and an insulating plate interposed therebetween, and these members are tightly fastened with fastening bolts from both ends.
A fuel cell configured as such is operated in a high-temperature high-humidity state, and a trace amount of hydrofluoric acid is eluted from a solid polymer electrolyte membrane (hereinafter, may be referred to as “electrolyte membrane”). Therefore, in order to enable fuel cells to endure such conditions, a sealing material 16 is required to have heat resistance, hot water resistance, and acid resistance.
Regarding such a sealing material, the means of PTL 1 to PTL 5 have been suggested.